Providing a stable opto-mechanical platform with a reduced overall package size is generally a requirement for optical telecommunications modules. These requirements apply to diffraction grating-based optical modules such as, for example, Dense Wavelength Division Multiplexer (DWDM) modules and Optical Performance Monitor (OPM) modules. In addition, these modules must provide acceptable optical performance over a specified operating temperature range (e.g., −5° C. to 70° C.). These modules must also generally withstand storage temperatures (e.g., −40° C.) to 85° C.) for extended periods of time.
One method to help achieve this so-called athermal performance is to make use of a cylindrical opto-mechanical geometry. That is, a module may be cylindrical in shape, with the cylindrical axis coincident with an optical axis of resident optical elements, similar to a lens barrel. The cylindrical geometry provides more mechanical stiffness relative to other geometries, thus improving the mechanical stability of the module. However, the cylindrical geometry may also increase the size of the module unnecessarily since the clear aperture of the optical elements within such a module is generally elliptical, with the long axis corresponding to the dispersion axis.
In view of the foregoing, it would be desirable to provide an opto-mechanical platform which overcomes the above-described inadequacies and shortcomings in an efficient and cost effective manner.